1. Field of the Invention
The present invention relates to an ink jet recording apparatus and a control method therefor.
2. Description of the Related Art
A serial ink-jet recording apparatus (serial ink-jet printer) in the related art in which a recording operation is performed while a carriage having a recording head moves in the moving direction thereof (main scanning direction) includes a buffer memory. The buffer memory is configured so as to be wider in the main scanning direction than a medium on which data is recorded (hereinafter referred to as “recorded medium”) and to be as wide as or wider than the recording head in the direction in which the recorded medium is fed (sub-scanning direction).
As record data, which is stored in the buffer memory, is transferred to the recording head, the recording head is scanned in the main scanning direction so that the data is printed on the recorded medium.
If the record data contains a sequence of null data in the direction in which the recorded medium is fed, the so-called “null skip” control is performed so as to store the record data in which the null data is skipped so as not to store the null data in the record buffer.
In a mechanism for increasing the recording density at which an image is recorded using a recording head with a predetermined recording density (for example, 600 dots per inch (dpi)) in the sub-scanning direction, two nozzle arrays are staggered in the main scanning direction so as to interpose nozzles in one array between nozzles in the other array. For example, when two 600-dpi recording heads are shifted with respect to each other by 1200 dpi, the nozzles give a resolution of 1200 dpi in a staggered array in the sub-scanning direction.
However, when two nozzle arrays are arranged side-by-side, a complex control operation is required for storing the record data corresponding to each nozzle in the buffer memory.
Specifically, the data arranged in the direction of the nozzle arrays are read in a predetermined unit (for example, 32-bit raster data), and is divided into 16-bit raster data to be distributed to each of the two nozzle arrays to allocate the data to each of the nozzles.
Furthermore, the null skip processing must be performed in data units corresponding to the actual arrangement of nozzles.